A thin film transistor liquid crystal display (TFT-LCD) has the characteristics of small size, low power consumption, no radiation, relatively low cost on manufacturing, etc., and occupies a dominant position in the current market of flat panel displays. The main structure of the TFT-LCD is an array substrate and a color filter substrate which are oppositely arranged to form a cell. A sealed space is formed between the array substrate and the color filter substrate by a sealant. In the sealed space, liquid crystal molecules are filled. The sealant is located in a non-display region on a periphery of a display region. A functional film layer is also formed inside of the array substrate and the color filter substrate, the functional film layer is used to ensure that the liquid crystal molecules are aligned as required, so as to form a pretilt angle. The functional film layer is also known as an alignment layer.
As a further pursuit of the visual appearance of a display, a narrow-frame flat panel display has become a trend of the future. In the narrow-frame flat panel display, the non-display region is very small. Since there is a process deviations for coating the alignment layer and an edge of the alignment layer has a region having nonuniform thickness, it is difficult for the alignment layer to ensure that the display region is covered completely and ensure a normal display of the display region, while not being interfered with the sealant region and not affecting the product quality.